feat: package continuity plugin MVP docs and receipt store

plugins/continuity/test/continuity.receipt-validator.test.mjs

@@ -0,0 +1,44 @@
+import assert from 'node:assert/strict';
+import { isValidReceipt, validateReceipt } from '../src/continuity/receipt-validator.mjs';
+
+function test(name, fn) {
+  try {
+    fn();
+    console.log(`ok - ${name}`);
+  } catch (error) {
+    console.error(`not ok - ${name}`);
+    throw error;
+  }
+}
+
+test('accepts full receipt contract', () => {
+  const receipt = {
+    planId: 'plan-1',
+    currentTask: 'task-7',
+    nextDerivedAction: { type: 'message_subagent' },
+    dispatchedAt: '2026-04-24T09:00:00.000Z',
+    dispatchRunId: 'run-1',
+    childSessionKey: 'child-1',
+    replyClosureState: 'completed',
+  };
+
+  const result = validateReceipt(receipt);
+  assert.equal(result.ok, true);
+  assert.equal(isValidReceipt(receipt), true);
+});
+
+test('rejects non-object receipt', () => {
+  const result = validateReceipt(null);
+  assert.equal(result.ok, false);
+  assert.match(result.errors.join('\n'), /expected object/);
+});
+
+test('rejects missing required fields', () => {
+  const result = validateReceipt({ planId: 'plan-1' });
+  assert.equal(result.ok, false);
+  assert.match(result.errors.join('\n'), /currentTask/);
+  assert.match(result.errors.join('\n'), /nextDerivedAction/);
+  assert.match(result.errors.join('\n'), /replyClosureState/);
+});
+
+console.log('continuity.receipt-validator.test.mjs PASS');